The present invention relates to a hydrocarbon-containing gas for a fuel cell having a low content of carbonyl sulfide (COS), a method for removing sulfur compounds contained in a hydrocarbon-containing gas and a production process for hydrogen for a fuel cell. More specifically, the present invention relates to a method for efficiently removing all of sulfur compounds contained in a hydrocarbon-containing gas to a low concentration even at a room temperature and a process for reforming the desulfurization-treated hydrocarbon-containing gas obtained by the method described above to economically advantageously produce hydrogen for a fuel cell.